Tester apparatus for oil wells or the like



G. L. LOOMIS TESTER APPARATUS FOR OIL WELLS OR THE LIKE June 12, 1962 Filed Aug. 11, 1958 :EIE 1 R m N E 5 WW 0 o L L n n k 6 .2 a

BYM zMAQ ATTORNEYS its The present invention relates to a tester apparatus and, more particularly, to an improvement in providing or forming a seal or barrier by a tester apparatus adapted for use in testing sections of oil well pipe or casings for leaks. This application is an improvement of the apparatus disclosed in my co-pending application Serial No. 480,741, filed January 10, 1955, now U.S. Patent No. 2,841,007.

In present day drilling of oil wells, it is highly desirable to test the Well pipe or casing as it is being run so that each section or stand, as well as its coupling or collar, will be run into the well in a perfect condition. A typical tester apparatus and the method of testing sections or" well pipe is disclosed in my US. Patent No. 2,731,827, issued January 24, 1956, as well as in my aforementioned co-pending US. application, Serial No. 480,741, now US. Patent No. 2,841,007.

Since present day wells are requiring flow tubing capable of withstanding extremely high pressures encountered in deep wells, accordingly it has been necessary to increase the test pressures applied by the testing tools. Present day requirements make it necessary to test the well tubing and the collar joints at pressures of 20,000 lbs. per square inch or higher and such testing has caused difliculties when using resilient packers made of rubber or composition as the rubber or composition will cold flow past the conventional packer head or abutments. Heretofore eflorts have been made to obviate cold flowing of the packer by providing expansible segmental packer back-up rings capable of expanding with the packer to thereby prevent extrusion past the packer head or abutment. Such prior packer back-up rings have encountered certain difliculties in that they do not completely prevent extrusion of the packer or they fail after repeated use due to cracks sustained therein.

An object of the present invention is to provide a tester apparatus with an improved packing structure capable of repetitions use in testing tubing at high pressures.

Another object of the present invention is to provide a tester apparatus with an improved packing structure utilizing an expansible packer back-up ring, the back-up ring providing for the prevention of extrusion of the packer longitudinally between the flow tubing and the packer head and radially outwardly between the back ring and the packer head.

Still another object of the present invention is to provide a tester apparatus having an improved packing structure utilizing an expansible segmental packer back-up ring which is capable of being expanded simultaneously with the packer and without the necessity of special mandrels or the like.

Still another object of the present invention is to provide a packing structure for use in forming a seal between any rod-like elements and the interior wall of a pipe or the like, the packing structure including a segmental expansible packer back-up ring provided with segments overlapping both circumferentially and radially, and also the packer back-up ring being capable of continuous and repetitious use.

While the present invention is primarily an improvement of providing a means utilized on a tester tool for forming a seal or barrier, it is of course within the scope of the present invention that the packing structure is capable of use in any type of pipe where it is desirable to form a seal between a rod-like element and the sur- Patented June 12, 1962 rounding wall of the pipe. Therefore, while the invention will be described in combination with a testing tool, it will be appreciated that the packing structure is capable of other uses and that the invention is not to be limited specifically to tester apparatus.

The foregoing and other objects of the present invention will appear more clearly in the following specification, claims, and drawings in which:

FIGURE 1 is a sectional view of tubing disclosing in elevation a tester apparatus embodying the present invention lowered therein.

FIGURE 2 is an enlarged fragmentary vertical section illustrating the tester apparatus and one of its packing structures.

FIGURE 3 is an enlarged side elevation of the segmental packer back-up ring.

FIGURE 4 is a top plan view of the segmental packer back-up ring of FIGURE 3.

FIGURE 5 is a perspective view of two of the arcuate segments of the packer back-up ring of FIGURES 3 and 4, the segments being viewed from interior of the ring and reversed.

FIGURE 6 is a sectional view of one segment taken on the line 66 of FIGURE 5, the dotted lines of FIG- URE 6 showing movement of one element of the segment with respect to the other element of the segment.

FIGURE 7 is an enlarged vertical sectional view of the expansible segmental packer back-up ring shown in FIGURE 3;

Referring now to the drawings wherein like character or reference numerals represent like or similar parts, the tester apparatus disclosed in FIGURE 1 includes an elongated tester body generally designated by the numeral 10, the tester body having a center section or portion 12 of slightly less diameter than oil well flow tube 14. Extending from each end of the center portion 12 of tester body 10 are intermediate body portions 16 (FIGURE 2) having a diameter slightly reduced with respect to the diameter of the center portion 12. Elongated cylindrical stems or rod-like elements 18 extend fromeach of the intermediate portions 16. As shown in FIGURE 1 a packing structure generally designated 20 is provided on the stems 18, the packing structure 20 being capable of forming a seal with the encircling wall of the pipe 14 so as to provide a sealed-off area therebetween to which fluid under pressure is applied to test the section of well pipe or the collar joint attaching two sections of well pipe together.

The tester body 12 is provided with a longitudinal bore 22 closed at its lower end by a cap member 24. A cou pling 26 threaded onto the upper stem 18 couples the tester apparatus to flexible tubing 28 which is suitably connected to apparatus -for supplying hydraulic fluid under pressure to tester apparatus. Such apparatus for supplying hydraulic fluid under pressure and supporting the tester tool within the well tubing is shown in my aforementioned US. Patent No. 2,731,827.

A pressure responsive valve generally indicated at 30 is provided in the center portion 12 of tester body 10. The valve 30 is operable by fluid pressure at a predetermined pressure and after the packing structures 20 have sealed olf a section of well pipe. It is then opened to permit test fluid to flow from within the tester body outwardly to the sealed-off area between the packing structures 20. A second valve generally indicated at 32 is provided in the center section 12 of tester body 10, this valve being fluid pressure operated to permit flow of test fluid from between the packing structures 20 to the inside of the tester tool when the pressure of test fluid in the bore 22 is relieved. In other words, when it is desired to change the position of the test tool in the flow tubing, the pressure applied to the test tool for test purposes is relieved and consequently the valve 32 opens resulting in the flow of test fluid from the area being tested through the valve back into the test tool.

Referring now in detail to FIGURES 2 through 7, each of the packing structures 20, which are identical in both construction and operation, includes a substantially cylindrical packer 34, an abutment or packer head 36 and a piston 38. Movement of the piston 38 against the end of packer 34 causes the packer 34 to compress longitudinally and expand transversely into sealing engagement with the wall of the flow tubing 14. In more detail, the piston 38 is cup-shaped and provided with a cylindrical skirt 40 slidable on the intermediate portion 16 of tester body 10. Piston 38 is provided with a head portion 42 which abuts against the end of the resilient packer 34. Suitable rings '44 are carried in the piston head 42 and provide a seal between the head and the stem 18. In addition, a suitable O-ring 46 is carried in the intermediate portion 16 of tester body so as to form a seal between the cylindrical skirt 40 and the intermediate portion 16 of the tester body.

A laterally extending passage 48 is provided in each of the stems 18 adjacent the point where the stems are integrally connected to the intermediate portion 16 of tester body 10. The passages 48 place the under-surface of the heads 42 of the pistons 38 in constant open communication with the longitudinally extending bore 22. Consequently, when fluid pressure is first applied to the bore 22 of the tester body 10, the pressure will cause the pistons to move outwardly away from the center section 12 of the tester body to thereby cause the packer to compress longitudinally against the packer head and expand transversely into engagement with the tubing being tested as fully disclosed in my aforementioned co-pending application, Serial No. 480,741, now US. Patent No. 2,841,007.

As previously mentioned resilient packers such as the packer 34 have a tendency to cold flow at extremely high pressures. In order to prevent the resilient packer 34 which is made of an elastomeric material, such as synthetic rubber substitutes or rubber, from extruding or flowing past the packer head or abutment 36, an expansible segmental packer back-up ring 50 is provided. The packer back-up ring 50 is capable of expanding simultaneously with the packer 34 so that there is always a surface present to prevent or block the flow of the packer past the packer head 36 as will be described in more detail later in the present specification.

Referring now specifically to FIGURE 2 the resilient packer 34 is provided with a main body portion 52 having a relaxed diameter slightly less than the diameter of the tubing 14. One end portion of the packer 34 has an exteriorly reduced diameter as indicated at 54, this end portion being adapted to receive the back-up ring 50. The reduced end portion 54 is provided at the very end of the packer with an annular groove 55, the purpose of this groove being explained in more detail later in the specification. As shown in FIGURE 2 packer backup rings 50 fits on the reduced end portion 54 of packer 34. The end of the packer extends through the ring 50 and abuts against the packer head 36. The upper packer head 36, which is threaded onto the threaded end 60 of stem 18, is locked against movement by the coupling member 26 as this member serves a dual function of coupling the tester tool to the flexible hose 28 as Well as locking the head 36 against longitudinal movement on the tester body. The lower packer head 36 is similarly locked against movement but the cap member 24 serves as the locking means.

Referring now to FIGURES 3 to 7, inclusive, the packer back-up ring 50 includes a plurality of identically shaped arcuate segments 64 held together as a unit by a pair of spring elements or snap rings 66 positioned in grooves 68 provided on the exterior surface of the segments. The segments 64 overlap each other in both a radial and circumferential direction and by having the segments overlapping in this manner, when the ring is expanded, there is no place for the packer 34 to flow when high pressures are encountered.

Each segment 64 includes a circumferentially extending portion 70 of less radial thickness than the total thickness of the segment and also of less longitudinal length than the total longitudinal length of the segment. Each segment 64 is also provided with a recess 72 of a size complementary to the size of the circumferentially extending projecting portion 70. The recess portion 72 is adapted to receive the projection or overlapping portion 70 of an adjacent segment 64, the free end 74 of the circumferentially extending portion 70 abutting the wall 76 of the recess 72 when the back-up ring is in its retracted position as shown in FIGURE 3. The recess 72 is provided with a radially extending surface or wall 78 which overlaps the surface 80 of the projecting portion 70 of an adjacent segment. As is now obvious, when the packer 34 is compressed longitudinally against the abutment or packer head 36 and expands transversely, the portion 54 of the packer on which the ring is mounted will also expand transversely in all directions causing the back-up ring to expand. By providing segments so shaped that they overlap both radially and circumferentially, the packer 34 cannot extrude or flow past the packer head 36 when high pressures of 20,000 lbs. per square inch or higher are applied to the packer.

In order to prevent extrusion of the packer radially outwardly between the back-up ring 50 and the packer head 36 in the area indicated by the arrow A in FIG- URE 2, the segments of the packer back-up ring 50 are each provided with a radially inwardly depending flange 82, the flange 82 of each segment being received in the annular groove 55 on the end of the packer. The flanges 82 of the segments define an annular flange 84 when the packer back-up ring is in the retracted position as shown in FIGURE 4. The flanges 82 cause the packer 34 in the area of its reduced end portion 54 to compress inwardly and tightly against the stem 18 of the tester body and consequently there is no flow through the annular space A between the back-up ring 50 and the abutment or packer head 36.

While it is desirous that oil well flow tubing be perfectly circular in cross section, it is well-known that such tubing may be slightly out-of-round due to pressures it may encounter or due to manufacturing tolerances. The packer back-up ring 50, being made of a plurality of segments 64 can compensate for the slight irregularities found in tubing being tested or tubing where it is desirous to form a seal between the wall of the tubing and a rodshaped element. To further compensate for such irregularities and to provide a segment which will not fracture longitudinally along the line marked B-B in FIGURES 5 and 6, each segment is made of two arcuate elements C and D, the elements being secured together by a radially extending pin or rivet 90. The element C forms the circumferentially extending projection or portion 70 and the exterior peripheral wall of the ring when in retracted position. On the other hand the element B provides the recess '72 for the segment and the interior wall of the ring 50 when in retracted position. Also, the element D contains the radially inwardly extending flange 82.

The rivet which secures the element C to the element D to form the segment 64 extends through a slightly oversized hole 92 so that there may be relative limited movemcnt between the elements C and D. Referring specifically to FIGURE 6 the dotted line position of the element C is the position the element would assume when the segmental ring 50 is expanded outwardly and engages a surface which is not necessarily a true circle. It will be noted that the element C pivots slightly at F on the element D. By making each segment of two elements C and D the elements having slight movement with respect to one another it has been found that the segmental packer back-up ring of the present invention has an increased life in that it may be used over and over during the course of testing without fatigue setting up in the metal which would'eventually cause a crack in the thin wall of the segment where the recess 72 is located.

From the above description it will be appreciated that the testing tool embodying the improved packing structures 20 may be used over and over again in conducting tests at high pressures on oil well flow tubing or casings. The barriers formed by the packing structure 20 have a longer life because the expansible packer back-up ring 50 effectively prevents the resilient packer 34 from extruding both longitudinally along the wall of the well pipe and radially between the packer head 36 and the ring 50. Each of the packing structures 20 are substantially identical in construction and the fluid pressure used for testing the section of well pipe is first app-lied to the pistons 38 to cause the packers 34 to initially seal against the wall of the well pipe. Once the barriers on each side of the area to be tested have been established, fluid under pressure opens the valve 30 and flows into the sealedoff area. The pressure is increased to a predetermined desired amount and the more the pressure is increased the tighter the packer 34 will seal against the wall of the pipe 14 as the fluid will get under the lip 60" of the packer and will additionally compress the packer. The back-up ring positively prevents the cold flowing of the packer at extremely high pressures and the construction of the segments of the back-up ring 50' is such that the segments have longer life as there is little chance of cracks occurring because of metal fatigue.

While the invention has been primarily disclosed in relation with a tester tool for oil well flow tubing, it is of course Within the scope of the present invention that the improved packer structure 20 could be used in flow tubing or casing where it is desired to form a seal between a rod-like element and the wall of the tubing or casing.

The terminology used in this specification is for the purpose of description and not for limitation, as the scope of the invention is defined in the claims.

I claim:

1. In a packing structure for forming a seal between a rod-like element and -a surrounding wall of well pipe or the like: a substantially cylindrically shaped resilient packer mounted on the rod-like element, said resilient packer having a main body portion with a diameter smaller than the diameter of the pipe and one end portion of exteriorly reduced diameter; an expansible segmental packer back-up ring mounted on the reduced portion of said packer and having an outside diameter substantially equal to the diameter of the body portion of said packer, the reduced end portion of said packer extending through said ring, said ring including a plurality of arcuate segments, each of said segments overlapping an adjacent segment and each of said segments comprising two arcuate elements, means coupling said two elements together for limited relative movement of one element with respect to the other element; abutment means carried by said rod-like element and engaging the end of said packer extending through said back-up ring; and means causing said packer to compress longitudinally and expand transversely into engagement with the wall of the pipe, said packer also expanding transversely in its reduced end portion to thereby cause said back-up ring to expand toward the wall of the pipe.

2. In a packing structure for forming a seal between a rod-like element and a surrounding wall of well pipe or the like: a substantially cylindrically shaped resilient packer mounted on the rod-like element, said resilient packer having a main body portion with a diameter smaller than the diameter of the pipe and one end portion of exteriorly reduced diameter; an expansible segmental packer back-up ring mounted on the reduced portion of said packer and having an outside diameter substantially equal to the diameter of the body portion of said packer, the reduced end portion of said packer extending through said ring; said ring comprising a plurality of arcuate segments overlapping one another at least circumferentially, each of said segments including a first element overlapping a second element, means coupling said first element and said second element together, said coupling means including a radially extending rivet loosely positioned through said first and second elements whereby one element has relative limited movement with respect to the other element; abutment means carried by said rodlike element and engaging the end of said packer extendiug through said back-up ring; and means causing said packer to compress longitudinally against said abutment means and expand transversely into engagement with the wall of the pipe, said packer also expanding transverselyin its reduced end portion to thereby cause the back-up ring to expand outwardly toward the wall of the pipe.

3. A packing structure of the character described in claim 2 wherein said means for causing said packer to compress longitudinally includes a piston member movable longitudinally on said rod-like element, said piston member abutting the end of said packer opposite the end of the packer which is in engagement with said abutment means.

4. An expansible packer back-up ring for use with a resilient packer comprising: a plurality of arcuate segments; resilient means circumscribing said segments for retaining them in retracted position as a unit; each of said segments comprising arcuate elements overlapping one another radially, and a radially extending pin loosely positioned through and coupling said arcuate elements together to form said segments, said pin permitting relative limited movement between said coupled elements when said ring is expanded.

5. An expansible packer back-up ring for use with and circumscribing the end of a resilient packer, said ring comprising a plurality of arcuate segments overlapping one another both circumferentially and radially, resilient means circumscribing said segments for retaining them in a retracted position as a unit, each of said arcuate segments comprising a pair of arcuate elements overlapping one another radially, a radially extending pin loosely positioned through and coupling each pair of elements together as segments, said pin permitting limited movement of one element with respect to the other element and each of said segments having a radially inwardly extending flange, the radially inwardly extending flange of said segments defining an annular inwardly extending flange when said segments are in a retracted position.

6. In a packing structure for forming a seal between a rod-like element and a surrounding wall of well pipe or the like: a substantially cylindrical shaped resilient packer mounted on the rod-like element, said resilient packer having a main body portion with a diameter smaller than the diameter of the pipe and one end portion of exteriorly reduced diameter, the end of the reduced end portion of said packer having a groove therein; an expansible segmental packer back-up ring mounted on the reduced portion of said packer and having an outside diameter substantially equal to the diameter of the body portion of said packer, the reduced end portion of said packer extending through and out of said ring, said ring including a plurality of arcuate segments overlapping one another both radially and circumferentially, each of said segments having an inwardly extending flange disposed adjacent its end and into the groove in the reduced end portion of said packer; means circumscribing said arcuate segments for retaining them in retracted position as a unit; abutment means carried by said rodlike element and engaging the end of said packer extending through and out of said ring, said abutment means being spaced from said packer back-up ring at least when said packer back-up ring is in retracted position; and means engaging the opposite end of said packer for causing said packer to compress longitudinally against said abutment means and expand transversely into engagement with the wall of the pipe, said packer also expanding transversely in its reduced end portion to thereby cause the packer back-up ring to expand outwardly toward the wall of the pipe to prevent extrusion of the packer.

7. A packing structure of the character described in claim 6 wherein each of said arcuate segments include a pair of arcuate elements, and a radially extending pin loosely positioned through and coupling each pair of elements together as segments, said pin permitting limited movement of one element with respect to the other element.

References Cited in the file of this patent UNITED STATES PATENTS Heeter Dec. 15, Townsend Aug. 11, King Feb. 6, King June 5, Barnes July 15, Potts Mar. 22, Fewel Aug. 16, Loomis Oct. 1, Lynes Feb. 25, Conover Apr. 22, Loornis July 1, Johnston Sept. 2, Baker May 5,

Baker July 28, 

